An Individual Tax Identification Number (ITIN) is for people who live in the United States but do not qualify for a Social Security Number. If you’re here working in the US, you should have been issued a Social Security Number, but your spouse and children weren’t. In order to claim them on your US income tax return, you’ll need to obtain ITINs. Here are my instructions for the best way to do it.

Each person needing an ITIN will have to complete a separate form. For example: if you want to claim your wife and your daughter on your US tax return, then you’ll need two separate forms.
In the section of the form where they ask for identifying documents, if you’ve got a passport, that’s your document. Don’t even consider the other documents if a passport is available; it can be a headache using them.

You will apply for the ITIN at the same time that you file your income tax return. You will attach the W7 form (or forms) to the front of your tax return. You will list your dependents’ names on the return and in the section that says “Social Security Number” you will write “applied for.” Note: you’re not applying for a Social Security Number, it’s an ITIN number and that’s understood because you’re submitting the W7 with the form. ITIN numbers are different from Social Security Numbers and the IRS computers recognize that; you’re not being dishonest in any way.

If you read the instructions to the form W7, it will tell you about mailing the return and getting your documents notarized, etc. Don’t do that! The best and fastest way to process getting your ITIN numbers is for you to go in person, with your documents and your dependents, to the nearest IRS office to file your taxes in person. The IRS agent at the desk will examine your documents right there, stamp what needs to be stamped, and will send your return off to the correct processing house from there. If there’s anything wrong with the paperwork, you’ll find out right then, and not three months later when they ask you to resubmit everything.

Because your tax return is being submitted by paper, there will be the additional delay associated with the ITIN, and your tax refund will be very slow. Do not be surprised if it takes 12 weeks for them to process your return. Once the ITINs are processed, you’ll receive paperwork in the mail. You’ll use those numbers on future tax returns and you won’t have to go through the process again. You’ll even be able to e-file which gives you a much faster refund.

Extra stuff to know: An ITIN number allows you to file an income tax return and claim a spouse or a dependent. There are some tax benefits (most notably the Earned Income Credit) that are not allowed with an ITIN, but only with a Social Security Number. If your family’s status changes and you later obtain Social Security Numbers for them, you are allowed to amend your prior year’s tax returns (up to three years) to claim any tax benefits that you missed earlier because you used an ITIN number.

Heads up about tax software: Some software programs can’t process a tax return correctly if there isn’t a number in the social security box. They will generate a “fake” number to create the return and then it has to be deleted at the end. Make sure that your return says “applied for” in the social security box before you submit it and that there’s no fake number in there. It will delay the processing of your return by months.